Feany M B, Yee A G, Delvy M L, Buckley K M
Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115.
J Cell Biol. 1993 Nov;123(3):575-84. doi: 10.1083/jcb.123.3.575.
We expressed the synaptic vesicle proteins SV2, synaptotagmin, and synaptophysin in CHO fibroblasts to investigate the targeting information contained by each protein. All three proteins entered different cellular compartments. Synaptotagmin was found on the plasma membrane. Both SV2 and synaptophysin were sorted to small intracellular vesicles, but synaptophysin colocalized with early endosomal markers, while SV2 did not. SV2-containing vesicles did not have the same sedimentation characteristics as authentic synaptic vesicles, even though transfected SV2 was sorted from endosomal markers. We also created cell lines expressing both SV2 and synaptotagmin, both synaptotagmin and synaptophysin, and lines expressing all three synaptic vesicle proteins. In all cases, the proteins maintained their distinct compartmentalizations, were not found in the same organelle, and did not created synaptic vesicle-like structures. These results have important implications for models of synaptic vesicle biogenesis.
我们在CHO成纤维细胞中表达了突触小泡蛋白SV2、突触结合蛋白和突触素，以研究每种蛋白所包含的靶向信息。这三种蛋白均进入了不同的细胞区室。突触结合蛋白定位于质膜上。SV2和突触素均被分选至细胞内的小泡中，但突触素与早期内体标记物共定位，而SV2则不然。尽管转染的SV2与内体标记物分离开了，但含有SV2的小泡并不具有与真正的突触小泡相同的沉降特性。我们还构建了同时表达SV2和突触结合蛋白、同时表达突触结合蛋白和突触素以及表达所有三种突触小泡蛋白的细胞系。在所有情况下，这些蛋白都保持其独特的区室化状态，未在同一细胞器中被发现，也未形成类似突触小泡的结构。这些结果对突触小泡生物发生模型具有重要意义。
